http://chap.sch.ir/sites/default/files/books/93-94/47/099-130-C489-8.pdf

https://ftp.utcluj.ro/pub/users/cemil/asm/CH02.PDF

http://bnrg.cs.berkeley.edu/~randy/Courses/CS150.F00/CLD2/chapter02.pdf

http://ocw.nctu.edu.tw/course/digital design/Logic DesignCh02.pdf